This invention relates to organic cutting fluids that can facilitate the abrading, cutting or machining of vitreous, crystalline, or aggregate materials, and that may also be used as protective coatings on vitreous, crystalline, or aggregate materials.
Cutting, abrading, grinding, polishing, and other machining operations performed upon glass, ceramic, metal, stone, or other vitreous, crystalline, or aggregate materials have to date been associated with problems such as rapid dulling of the cutting or grinding tools, long processing times, and unduly rough or excessively scratched final surfaces. All of which have resulted in large amounts of waste, high manufacturing costs, shortened life of tools, and less than desired end products.
To minimize these problems, the machining of vitreous, crystalline, or aggregate materials often require lubrication with cutting or wetting fluids such as water or other liquid solutions. Cutting fluids typically reduce fiction between the cutting edge of a machining tool and the material being worked upon. Some cutting fluids also protect the workpiece from scratches and contamination caused by the deposit of abrasive particles or chips made during the machining process on workpiece surfaces. In general, a cutting fluid can also function as a coolant for the cutting or grinding tool.
In attempts to enhance the cutting or abrading actions and increase the better finishing of surfaces, cutting fluids used to date have fallen into four general categories of: (1) straight oils, usually light mineral oils or kerosene; (2) water-soluble emulsions which contain oil and surfactants for emulsifying the oil; (3) semi-synthetic types which contain relatively small amounts of oil and large percentages of surfactants or detergents; and (4) synthetic, chemical or solution types which contain no oil, but rely on various chemical compounds to achieve desired properties. The cutting fluid formulations in the first three categories, which require surfactants, traditionally use anionic or non-ionic surface-active agents for reducing surface tension, supplying lubricity and emulsifying oil content. The cationic fluids found in the fourth general category have traditionally not performed well as glass or ceramic machining fluids, nor have they been readily accepted for such purposes in view of one or more of their draw backs, such as excessive foaming, or the deposit of difficult to remove residue upon the machines and workpieces. Additionally, the lubricating properties of prior art cationic fluids are less than optimum and some have been excessively corrosive to machinery.
In the past, cationic compounds have been used in rock drilling but have not performed well as cutting fluids for operations on glass or glass-ceramic substrates. Some of the drawbacks include excessive foaming, the deposit of difficult to remove residue upon the machining tools and workpieces, the slow settling of cut particulate residue in the cutting fluid and difficult to remove from the workpiece. Moreover, the lubricating properties of prior art cationic fluids are less than optimum and some have been excessively corrosive to the machining tools. As a result of some of these drawbacks, the current predominant practice is to use plain water as the lubricating and flushing fluid when cutting or abrading glassy, crystalline or aggregate materials. Thus, there is a need for a novel cutting fluid used for machining glass, glass-ceramic, silicon, crystalline, and stone materials.
An objective of the present inventive cutting fluid is to achieve a slippery coating on all vitreous, crystalline or aggregate substrate surfaces that come into contact with the cutting surfaces of machining tools. With a slippery cutting fluid coating, the machining tool generates less friction and heat, tends to work easier against the substrate, removes more material at a faster rate, and creates potentially a better surface finish. By referring to these recited qualities, we hope to clarify the term xe2x80x9chigh performancexe2x80x9d by which we describe the inventive cutting fluid, and how the fluid enables a machine tool, such as a blade or drill bit, when used in conjunction with the cutting fluid, to cut or work faster without creating, or at least minimizing the occurrence of surface fractures or damage.
This invention incorporates organic molecules in aqueous solution and uses the solution as a cutting fluid during the working or machining of vitreous, crystalline, or aggregate materials, such as glassxe2x80x94especially, high ( greater than 85%) silicate-content glasses and/or fused silicaxe2x80x94quartz, crystalline bodies, glass ceramics, ceramics, rock or stonexe2x80x94especially, granite, marble, limestone, sandstonexe2x80x94concrete, metallic materials, silicon, silicon-carbide, and the like. The cutting fluid comprises a solution containing organic molecules capable of bonding with such vitreous, crystalline, or aggregate materials. It is believe that the organic molecules will improve the manufacturing productivity, surface finish quality, and decrease the incidence of sub-surface damage in these kinds of substrates.
In one embodiment of the invention the cutting fluid consists of organic molecules of selected from cationic phosphonium compounds in solution. In a preferred embodiment, silane solutions are used as cutting fluids. The silanes are organosilanes, siloxanes, or silanols, having molecular substituents that include alkyl, phenylated, branched, unbranched, or cyclic carbon groups, as well as oxygen and halides. It is believed that silanes have not been used as cutting fluids, especially for vitreous, crystalline or aggregate materials. Silane compounds exhibit properties that can form covalent bonds with a workpiece""s surfaces. The organic molecules bind rapidly to inorganic particles, such as glass, glass ceramics, ceramics, or other inorganic oxides. Ordinarily these particles or milled chips will clog the abrading surface of a cutting tool. The organic molecules prevent the inorganic particles from readily binding to each other and or the abrading surface of the cutting tool. Thus, when the tool remains largely free of particles (unclogged), the tool can cut faster, using less pressure, and cause less surface and subsurface damage.
As contemplated in this invention, cutting or abrading tools are kept free of substrate particulates and are prevented from clogging through out the normal cutting or machining process. Due to their covalent nature and lubricating properties, silane molecules in the cutting fluid tend to bond to the surfaces of the substrate materials, and lubricates the tool-workpiece interface, minimizing both tool-wear and heating due to friction. Moreover, minimal tool-workpiece interface pressures are required and cutting or machining times are substantially shortened with the resulting realization of considerable economic advantage and improved product quality. Additionally, in view of the free flowing characteristics of the inventive cutting fluid, it readily carries away grinding swarf and permits rapid settling of the swarf in the used fluid as a relatively hard and easily filtered precipitate.
Other advantages and characteristics of the invention will become apparent from the following detailed description read in conjunction with the accompanying illustrative drawings.